Answer: Long -term capital gain
Step-by-step explanation:
Serena is single, so based on the Taxpayer Relief Act of 1997, she would pay no capital gains tax on the first $250,000 gain.
Therefore, $300,000 - $250,000 = $50,000
The remaining $50,000 gain is taxable because of her being single and it has been her principal residence for three years.